Time relay for fluorescent lamps



June '16, 1942.

Filed March 30, 1940 INVENTOR a 5, auJr/A/ ATTORNEY Patented une l 6, 1942 UNITE "STATES ATENT OFF! RELAY FOR FLUORESCENT LAMPS Daniel S. Gustin, Bloomfield, N. J., assignor to Westinghouse Electric & Manufacturing Company, East Pittsburgh, Pa., a corporation Pennsylvania Application March 30, 1940, Serial No. 326,892

' 3 Claims. ((31.176-124) The present invention relates to gaseous electric discharge lamps particularly of the positive column cold-hot electrode type and has special reference to starting and operating circuits for such lamps.

Lamps of this general type are now well known to the art and in order for such lamps to be oper- It has also been proposed in the prior art to I provide 'a choke which supplies the high voltage surge and which limits the operating current with the choke opening and closing a pair of contact members upon the flow of electrical energy through the choke. Such contacts, however, have heretofore been operative in the atmosphere and, being affected by atmospheric conditions, cause very erratic operation of the switch as well as deterioration of the contact members.

It is accordingly the primary object of the pxesentinvention to provide a starting and operating circuit for a gaseous discharge lamp wherein an inductanceelement is employed which causes movement of a pair of contact members upon the flow of electrical energy therethrough and which inductance element is in no way affected by atmospheric conditions.

Another object of the present invention is the provision of a starting and operating circuit for a-gaseous discharge lamp wherein an .integral inductance and switching device having a pair of magnetizable contacts enclosed within an.

evacuated container is utilized for initially connecting the-inductance element to the source and in electrical parallel with the discharge lamp,

which contacts are opened upon the flow of electrical energy through the winding of the inductance to cause a high voltage surge to be impressed across the electrodes of the discharge 1 ,and Hi supported by magnetizable metal srips' IT and 18, such for example as iron. Thus the trical energy through the winding of the inductance element.

Still further objects of the present invention will .become obvious to those skilled in the art by reference to the accompanying drawing wherein:

Fig. 1 is a diagrammatic illustration of a startv ing and operating circuit for a gaseous discharge lamp in accordance with the present invention, and

Fig. 2 is a cross-sectional view of the novel inductance element of the present invention as used in the circuit shown in Fig. 1.

Referring now to the drawing in detaiL'there is shown in Fig. 1 a gaseous electric discharge lamp 5 which after evacuation is provided with an ionizable; medium, such as a few drops of mercury, together with a rare gas such as argon, neon, or helium to facilitate starting. Disposed at each end of the lamp 5 are electrodes 6 and I which are of the type commonly referred to in the art as the cold-hot type. In other words, the

electrodes are of suitable metal which when heated produces 'a copious flow of electrons, or they may boot the activated type wherein the metal is coated with a material which emits a copious flow of electrons..'

- As is well known, electrodes of this type are not heated from an exterior source, but are heated solely by the heat generated by the discharge. The electrode I is connected by a conductor 8 to one side L-- l of a suitable source of supply of the usual commercial potential of 115-230 volts. In a similar mann'er'th'e electrode 6 is connected by me'ansof a conductor 9 and the winding) of an inductance element l2 and an additional inductance or r'esisor l3 to the opposite side of the commercial source of supply L-Z.

As'shown more clearly in Fig. 2, the inductance I2 is provided with a .core comprising an evacuated container I4 which is provided with a pair of normally closed refractory'metal. contacts I5 contacts l5 and 16 are hermetically sealed from the atmosphere so that climatic conditions in no way impair the operation of thecontacts; and inasmuch as the container is evacuated, arcing between the contacts is substantially eliminated.

By reference again to Fig. 1, it will be noted that the contact terminal I5 is connected, by means of a conductor Hi to theconductor 9 and thus to the electrode 6 and one end of the winding I0 of the inductance element l2. Similarly the contact terminal I6 is connected by means of a conductor 20 to the conductor 8 and thus to the remaining electrode I of the lamp and onesidedf the source of supply L--l.

Due to the circuit arrangement thus described, it will he hated that two paralle'i circuits are "thus formed, one circuit extending from the source of supply L| through the conductors 8 and 20, the contacts I6 and I5, conductors I9 and 9, inductance winding l0, and an additional inductance or resistor l3 back to the opposite side of the source of supply L-2, while the other circuit extends from the S0111"! L-l through the conductor 8 to the electrode 1 of the lamp 5' and thence from the electrode 6 through the conductor 9, inductance l2 and resistor I3 back to the opposite side of the source of supply L2.,

Thus the effect of operation of the contacts l5 and I6 is to short-circuit the lamp 5.

Accordingly, upon closure of a suitable switch (not shown) current will flow through the first circuit above .described since the contact terminals l5 and I6 are initially closed. However, inasmuch as the resistance of the lamp 5 is initially exceptionally high and it is in effect short-circuited, no current flows through the parallel circuit including the lamp 5. When the current flows through the winding H! of the inductance element l2, the magnetic flux generated thereby causes opening of the magnetizable contacts l5 and I6.

This interruption of the circuit causes a high voltage surge from the winding ll) of the inductance element l2 which is impressed between the electrodes 6 and 1, and since this voltage is substantially higher than that available from the source L-l, L2, the resistance of the lamp 5 is broken down and a discharge will be initiated between the electrodes 6 and 'I. This discharge inductance element having its winding connected to said source and to one of the electrodes ofsaid.lamp, said inductance being wound upon accordingly ionizes the gas within the lamp 5 and the heat generated by the discharge heats the electrodes (Sand 1 to a temperature sumcient to produce a copious flow of electrodes which sustains the discharge.

During continuanceof the discharge, the inductance element l2 together with the additional inductance or resistor 13 serves tolimit current supplied to the lamp 5. Also, as the current con-- tinually flows through the winding III of the inductance during operation of the lamp 5, the magnetic flux generated .thereby maintains the contact terminals l5 and IS in an open position. Thus the inductance i2 is connected in a series circuit with the lamp 5 and upon opening of the contacts l5 and IS, the short-circuit condition of the lamp 5, which initially exists, is eliminated for the purposes of starting the lamp 5.

It thus becomes obvious to those skilled in the art that a starting and operating circuit for a gaseous discharge lamp is herein provided wherein an integral inductance and switching. device is provided having contacts which form the switch enclosed within an evacuated containera. core constituting a pair of normally closed magnetizable contacts enclosed in an evacuated container, one of which is connected to one end of the winding of said inductance for initially short-circuiting said lamp and operable upon the flow of current through said inductance to eliminate the short-circuit condition of said lamp and to cause a high voltage starting surge to be supplied by said inductance to said lamp and said contacts to be maintained in an open position during operation of said lamp by the flow of current through said inductance.

2. A starting and operating circuit for a gaseous electric discharge lamp provided with electrodes which supporta discharge when heated comprising a source of electrical energy for energizing said lamp, an inductance element having its winding connected to said source and one of the electrodes of said lamp, and said inductance element being wound upona core constituting an evacuated container provided with a pair of normally closed magnetiz-able contacts shielded from the atmosphere, one of which is connected to one end of said inductance winding for initially short-circuiting said lamp-and operable,upon current fiow through said inductance to eliminate the short-circuit condition of said lamp and to simultaneously cause a high voltage starting surge to be supplied by said inductance to said lamp and said contacts to be maintained in an open position during operation of said lamp by current flow through said inductance.

3. The combination with a gaseous electric discharge lamp provided with electrodes which support a discharge when heated, of a starting circuit for said lamp comprising an inductance element provided with a winding having one of its ends connected to a source of electrical energy and being wound'upon a core constituting an evacuated container provided with a pair of normally closed magnetizable contacts therein shielded from the atmosphere, one of said contacts being connected to the other end of the inductance winding and to one of the electrodes of said lamp and the other of said contacts being connected to said source and to the other electrode of said lamp whereby said contacts initially effect a short-circuit of said lamp; an operating circuit for said discharge lamp comprising the electrodes of the latter, the inductance winding and said source; and said inductance being operable upon the flow of current through said winding to cause separationof said contacts and elimination of the shortecircuit of said lamp with an attendant voltage surge from said inductance across the electrodes of said lamp and the energization of said operating circuit.

DANIEL S. GUSTIN. 

